Roll Threading Port Cutters.Internal Straight Thread O-Ring BossReamer pilot series porting tools profiles the MS16142/J514F/J1926 contour. The reamer pilot also sizes the minor diameter for one of three thread percentages 75%, 65% and 55% depending on the thread percentage required. Cutters are heat treated for toughness and durability. All tolerances are held within applicable Mil Specs. All grinding is done between centers to insure concentricity. Coolant Thru Available. All diameters and dimensions can be altered to meet your requirements.Cutters can be altered to meet your requirements.